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来源： [转载]IOS 通过摄像头读取每一帧的图片，并且做人脸识别(swift) – qg – 博客园
最近帮别人做一个项目，主要是使用摄像头做人脸识别
github地址：https://github.com/qugang/AVCaptureVideoTemplate
要使用IOS的摄像头，需要使用AVFoundation 库，库里面的东西我就不介绍。
启动摄像头需要使用AVCaptureSession 类。
然后得到摄像头传输的每一帧数据，需要使用AVCaptureVideoDataOutputSampleBufferDelegate 委托。
首先在viewDidLoad 里添加找摄像头设备的代码，找到摄像头设备以后，开启摄像头
captureSession.sessionPreset = AVCaptureSessionPresetLow
let devices = AVCaptureDevice.devices()
for device in devices {
if (device.hasMediaType(AVMediaTypeVideo)) {
if (device.position == AVCaptureDevicePosition.Front) {
captureDevice = device as?AVCaptureDevice
if captureDevice != nil {
println("Capture Device found")
beginSession()
}
}
}
}
beginSession,开启摄像头：
func beginSession() {
var err : NSError? = nil
captureSession.addInput(AVCaptureDeviceInput(device: captureDevice, error: &err))
let output = AVCaptureVideoDataOutput()
let cameraQueue = dispatch_queue_create("cameraQueue", DISPATCH_QUEUE_SERIAL)
output.setSampleBufferDelegate(self, queue: cameraQueue)
output.videoSettings = [kCVPixelBufferPixelFormatTypeKey: kCVPixelFormatType_32BGRA]
captureSession.addOutput(output)
if err != nil {
println("error: \(err?.localizedDescription)")
}
previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
previewLayer?.videoGravity = "AVLayerVideoGravityResizeAspect"
previewLayer?.frame = self.view.bounds
self.view.layer.addSublayer(previewLayer)
captureSession.startRunning()
}
开启以后，实现captureOutput 方法：
func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {
if(self.isStart)
{
let resultImage = sampleBufferToImage(sampleBuffer)
let context = CIContext(options:[kCIContextUseSoftwareRenderer:true])
let detecotr = CIDetector(ofType:CIDetectorTypeFace, context:context, options:[CIDetectorAccuracy: CIDetectorAccuracyHigh])
let ciImage = CIImage(image: resultImage)
let results:NSArray = detecotr.featuresInImage(ciImage,options: ["CIDetectorImageOrientation" : 6])
for r in results {
let face:CIFaceFeature = r as! CIFaceFeature;
let faceImage = UIImage(CGImage: context.createCGImage(ciImage, fromRect: face.bounds),scale: 1.0, orientation: .Right)
NSLog("Face found at (%f,%f) of dimensions %fx%f", face.bounds.origin.x, face.bounds.origin.y,pickUIImager.frame.origin.x, pickUIImager.frame.origin.y)
dispatch_async(dispatch_get_main_queue()) {
if (self.isStart)
{
self.dismissViewControllerAnimated(true, completion: nil)
self.didReceiveMemoryWarning()
self.callBack!(face: faceImage!)
}
self.isStart = false
}
}
}
}
在每一帧图片上使用CIDetector 得到人脸，CIDetector 还可以得到眨眼，与微笑的人脸，如果要详细使用去官方查看API
上面就是关键代码，设置了有2秒的延迟，2秒之后开始人脸检测。
全部代码：
//
// ViewController.swift
// AVSessionTest
//
// Created by qugang on 15/7/8.
// Copyright (c) 2015年 qugang. All rights reserved.
//
import UIKit
import AVFoundation
class AVCaptireVideoPicController: UIViewController,AVCaptureVideoDataOutputSampleBufferDelegate {
var callBack :((face: UIImage) ->())?
let captureSession = AVCaptureSession()
var captureDevice : AVCaptureDevice?
var previewLayer : AVCaptureVideoPreviewLayer?
var pickUIImager : UIImageView = UIImageView(image: UIImage(named: "pick_bg"))
var line : UIImageView = UIImageView(image: UIImage(named: "line"))
var timer : NSTimer!
var upOrdown = true
var isStart = false
override func viewDidLoad() {
super.viewDidLoad()
captureSession.sessionPreset = AVCaptureSessionPresetLow
let devices = AVCaptureDevice.devices()
for device in devices {
if (device.hasMediaType(AVMediaTypeVideo)) {
if (device.position == AVCaptureDevicePosition.Front) {
captureDevice = device as?AVCaptureDevice
if captureDevice != nil {
println("Capture Device found")
beginSession()
}
}
}
}
pickUIImager.frame = CGRect(x: self.view.bounds.width / 2 - 100, y: self.view.bounds.height / 2 - 100,width: 200,height: 200)
line.frame = CGRect(x: self.view.bounds.width / 2 - 100, y: self.view.bounds.height / 2 - 100, width: 200, height: 2)
self.view.addSubview(pickUIImager)
self.view.addSubview(line)
timer = NSTimer.scheduledTimerWithTimeInterval(0.01, target: self, selector: "animationSate", userInfo: nil, repeats: true)
NSTimer.scheduledTimerWithTimeInterval(2, target: self, selector: "isStartTrue", userInfo: nil, repeats: false)
}
func isStartTrue(){
self.isStart = true
}
override func didReceiveMemoryWarning(){
super.didReceiveMemoryWarning()
captureSession.stopRunning()
}
func animationSate(){
if upOrdown {
if (line.frame.origin.y >= pickUIImager.frame.origin.y + 200)
{
upOrdown = false
}
else
{
line.frame.origin.y += 2
}
} else {
if (line.frame.origin.y <= pickUIImager.frame.origin.y)
{
upOrdown = true
}
else
{
line.frame.origin.y -= 2
}
}
}
func beginSession() {
var err : NSError? = nil
captureSession.addInput(AVCaptureDeviceInput(device: captureDevice, error: &err))
let output = AVCaptureVideoDataOutput()
let cameraQueue = dispatch_queue_create("cameraQueue", DISPATCH_QUEUE_SERIAL)
output.setSampleBufferDelegate(self, queue: cameraQueue)
output.videoSettings = [kCVPixelBufferPixelFormatTypeKey: kCVPixelFormatType_32BGRA]
captureSession.addOutput(output)
if err != nil {
println("error: \(err?.localizedDescription)")
}
previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
previewLayer?.videoGravity = "AVLayerVideoGravityResizeAspect"
previewLayer?.frame = self.view.bounds
self.view.layer.addSublayer(previewLayer)
captureSession.startRunning()
}
func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {
if(self.isStart)
{
let resultImage = sampleBufferToImage(sampleBuffer)
let context = CIContext(options:[kCIContextUseSoftwareRenderer:true])
let detecotr = CIDetector(ofType:CIDetectorTypeFace, context:context, options:[CIDetectorAccuracy: CIDetectorAccuracyHigh])
let ciImage = CIImage(image: resultImage)
let results:NSArray = detecotr.featuresInImage(ciImage,options: ["CIDetectorImageOrientation" : 6])
for r in results {
let face:CIFaceFeature = r as! CIFaceFeature;
let faceImage = UIImage(CGImage: context.createCGImage(ciImage, fromRect: face.bounds),scale: 1.0, orientation: .Right)
NSLog("Face found at (%f,%f) of dimensions %fx%f", face.bounds.origin.x, face.bounds.origin.y,pickUIImager.frame.origin.x, pickUIImager.frame.origin.y)
dispatch_async(dispatch_get_main_queue()) {
if (self.isStart)
{
self.dismissViewControllerAnimated(true, completion: nil)
self.didReceiveMemoryWarning()
self.callBack!(face: faceImage!)
}
self.isStart = false
}
}
}
}
private func sampleBufferToImage(sampleBuffer: CMSampleBuffer!) -> UIImage {
let imageBuffer: CVImageBufferRef = CMSampleBufferGetImageBuffer(sampleBuffer)
CVPixelBufferLockBaseAddress(imageBuffer, 0)
let baseAddress = CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0)
let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer)
let width = CVPixelBufferGetWidth(imageBuffer)
let height = CVPixelBufferGetHeight(imageBuffer)
let colorSpace: CGColorSpaceRef = CGColorSpaceCreateDeviceRGB()
let bitsPerCompornent = 8
var bitmapInfo = CGBitmapInfo((CGBitmapInfo.ByteOrder32Little.rawValue | CGImageAlphaInfo.PremultipliedFirst.rawValue) as UInt32)
let newContext = CGBitmapContextCreate(baseAddress, width, height, bitsPerCompornent, bytesPerRow, colorSpace, bitmapInfo) as CGContextRef
let imageRef: CGImageRef = CGBitmapContextCreateImage(newContext)
let resultImage = UIImage(CGImage: imageRef, scale: 1.0, orientation: UIImageOrientation.Right)!
return resultImage
}
func imageResize (imageObj:UIImage, sizeChange:CGSize)-> UIImage{
let hasAlpha = false
let scale: CGFloat = 0.0
UIGraphicsBeginImageContextWithOptions(sizeChange, !hasAlpha, scale)
imageObj.drawInRect(CGRect(origin: CGPointZero, size: sizeChange))
let scaledImage = UIGraphicsGetImageFromCurrentImageContext()
return scaledImage
}
}
